The present invention relates to a rotary cutter of a mower for performing a mowing operation of grass or the like with a cord radially extended from a case which is rotatably driven by an engine or the like by way of a shaft.
Conventionally, a system which accommodates a cord in a reel has been used as this kind of technique. To deliver the cord when the free end side of the cord is worn, an engine is stopped and a cutter portion is partially disassembled, or bolts are loosened, or, as disclosed in Japanese Laid-open Publication SHO57-5608, a press body for moving a reel in an axial direction is mounted on a distal end of mounting shaft of a cutter and this press body is pushed into the reel while the cutter is rotated so that the phase between the reel and a housing is slipped thus enabling the delivering of the cord.
In the conventional rotary cutters having the above-mentioned constitutions, however, the former necessitates an extremely cumbersome manipulation for delivering the cord, while the latter pushes the press body into the reel by strongly striking the press body while the rotary cutter is rotated, the free end side of the cord is lowered and hence, the cord scatters pebbles or the like thus making the mowing operation dangerous. Further, in disassembling the rotary cutter, respective parts are separated and there has been a problem that extremely cumbersome steps and an utmost care become necessary in reassembling.
Further, in case the shape of the mower side is different, there has been a case that the cover cannot be mounted and hence, depending on the mower, the rotary cutter cannot be used.
It is an object of the present invention to provide a rotary cutter of a mower which can overcome the above-mentioned technical problems and is constructed such that the cord delivering operation which becomes necessary at the time that the free end side of the cord is worn out, can be carried out only at the time of the low speed rotation or the non-rotation of the rotary cutter so that the scattering of pebbles can be prevented and respective parts are prevented from being separated at random at the time of disassembling thus facilitating the reassembling, and a cover can be replaced depending on the shape of the mower side.
To achieve the above-mentioned object, the rotary cutter of the present invention includes a cord for carrying out a mowing of grass or the like along with a rotation thereof, a reel which accommodates the cord and allows delivering of the cord, while being intermittently rotated, a cover which covers a case accommodating the reel, and a press body which is protruded downwardly from the ease and is movable in an axial direction by pressing so as to intermittently rotate the reel, wherein the improvement is characterized in that means for biasing the press body in a direction to protrude the press body from the case is disposed between the reel and the press body, the press body and the case are engaged with each other such that the press body is slidable in an axial direction while a relative rotation between them is prevented, and by pressing the press body against the biasing means, a set of protrusions formed on the press body are engaged with or disengaged from protrusions formed on the reel so as to intermittently rotate the reel. Further, it is preferable to form an elongated hole in the reel into which one of a set of protrusions formed on the press body is fitted. Further, it is preferable to construct the rotary cutter of the mower such that ratchets held in place by the biasing means are expanded by a centrifugal force generated by the high speed rotation of the rotary cutter so as to prevent the axial slide movement of the press body. Further, it is preferable that the biasing means is constituted by a return spring disposed between the reel and the press body. Further, it is preferable that resiliently deformable pawls which are formed on the central portion of the press body are engaged with a cylindrical portion formed on the central portion of the reel. Furthermore, it is preferable that the cover is constituted by either a plastic member provided with a female threaded member at a central portion thereof for mounting the rotary cutter to the mower or a thin metal plate member provided with a hole at a central portion thereof for mounting the rotary cutter to the mower.